Definition & Information
There are various plastic pipe manufacturers and classes of pipe within manufacturers which relate to oxygen leaking into the water. Some basic tubing will inherently "breathe" thus allowing a continued minute flow of oxygen into the circulating water. Other tubing types have a special coating or other inherent shielding "component" which prevent or acts as a barrier for not allowing the oxygen to get into the circulating water.
Why is this a concern?
Pure water itself has no corrosive or aging component. How pure the water is when you start is not the concern because even if there is some oxygen in the water or impurities in a closed system they will soon deposit themselves and in essence the closed loop boiler system "cleans itself up" and winds up with pure water. Therefore, Electro Industries typically does not specify any special chemicals or special concern with the initial fill.
However, if oxygen is allowed to continually come into the water all components within the closed loop circulating system, over time, will be subject to a corrosive effect. The emphasis here is on all components within the circulating loop.
We hear some comments that using a ceramic or plastic boiler vessel prevents the need for oxygen barrier tubing. What about the pump, small orifices, and other components within the loop?
From Electro Industries' point of view, the vessel is not the concern. Our steel vessel is constructed in a manner in which it is very hard to conceive building up enough foreign material to have any effect on the vessel. Our stance on using only tubing or polyethylene tubing with oxygen Diffusion Barrier is to protect the end user from future problems relating to the overall loop system. It is very well known within the plumbing industry that pumps, zone valves, and other smaller restrictive components represent the key concern.